Impurity effects in a two-dimensional nonsymmorphic Dirac semimetal

Abstract

Abstract We theoretically study the impurity-induced states in a two-dimensional nonsymmorphic Dirac semimetal based on the T-matrix method. For calculating the local density of states, we find that for a Dirac system with two symmetry-inequivalent Dirac points the impurity states are similar to those in an ordinary two-dimensional Dirac sysytem. Whereas for the situation of two symmetry-equivalent Dirac points, the impurity states exhibit many distinct features, which are attributed to the spin-sublattice correlation associated with nonsymmorphic symmetry. In particular, these features are robust for the presence of the chiral symmetry-breaking term. Furthermore the impurity states in a Weyl semimetal and topological insulator with nonsymmorphic symmetries are derived and discussed. Thus the impurity effects of a two-dimensional nonsymmorphic Dirac semimetal can be used to probe the various topological nontrivial phases.